(a) Field of Disclosure
The present disclosure of invention relates to a mask that is usable for photoaligning an alignment layer of a Liquid Crystal Display (LCD), a photoalignment method using the same, and a liquid crystal display having the photoaligned alignment layer.
(b) Description of Related Technology
A liquid crystal display (LCD) is one of the most widely used flat panel displays (FPD) in the display arts. The LCD is typically composed of two display panels on which field generating electrodes are provided such as pixel electrodes on one panel and a common electrode formed on the other. A liquid crystal layer is generally interposed between the two display panels. In the liquid crystal display, voltages are applied to the field generating electrodes so as to generate electric fields extending through the liquid crystal layer, and then the alignments of liquid crystal molecules of the liquid crystal layer are determined by the strength and/or direction of the electric fields. Polarization of incident light rays passing through the liquid crystal layer may thus be controlled, thereby helping to form a desired image for display.
The orientation of liquid crystal molecules of the liquid crystal display are initially aligned in a predetermined direction, when an electrical field is not present, by use of an alignment layer formed for example with a rubbing process. Also, the liquid crystal molecules of the liquid crystal display may be initially aligned to have a pre-tilt angle by use of rubbing within a vertical alignment (VA) type of liquid crystal display such that the rotating direction of the liquid crystal molecules may be determined when next applying an electric voltage of given polarity.
The pre-tilt angle can be realized by the combination of a contact rubbing method and a light exposure alignment method. The alignment layer is rubbed by physical pressure using a roller in the contact rubbing method, and the alignment layer is then irradiated by ultraviolet (UV) rays in the light exposure alignment method, to thus define or refine the pre-tilt angle.
The photoalignment process can be designed to help increase the viewing angles of the display as compared to that which occurs when a constant same alignment angle is used symmetrically and uniformly throughout.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and it may contain information that does not form prior art that was already known to persons of ordinary skill in the pertinent art.